Futuristic weaponry.

1) Mono-molecular weaponry.
Weapons with edges or points that go down to a single molecule, of an extremely hard substance, such as a Carbon Nanotube, flawless diamond, Aggragated Diamond Nanorods, or maybe some other material.

There is also pizo-electric weaponry, which is based around a 'wire' maybe 100nm in diameter, but can be extruded by a 'hilt' up to several meters, more if you like. An electric charge vibrates the 'wire' at several million cycles a second, so that if the 'wire' comes into contact with most solid materiel it will vibrate straight through it, basically slicing it. Nearly everything except for a metal with a perfect molecular structure, such as an alloy of Irridium and Platinum. [Effectively stronger than diamond because of it's brittlness along natural impurities] This means it would slice straight through a modern day tank, building, anything, with next to no resitance.

2) High-Pressure Liquid [water] weapons.
Water jet cutting devices work on ejecting a stream of water at very high speeds, abbrading away a materiel. It is effectively natural errosion accelerated by orders of magnitude.

The most important of it's properties is that it does not create a HAZ spot [Heat Affected Zone] altering the properties of the material being cut.

A few materials cannot be cut by it, such as tempered glass which shatters when cut, regardless of the cutting technology used.

There exist many variations on this including abrasive water jets, percussive water jets, cavitation jets, and hybrid jets.

3) Plasma weaponry.

A few things need to be known about plasma, before continuing. In an atmosphere and electro-magnetic field [I.E. the surface of the Earth] the plasma is distorted at low velocitys and densitys by air resitance, and the tug of the EM field. These are somewhat minor effects however compared to the internal thermal/electric expansion of the energized particles.

Due to this effect their are two methods of bypassing this effect, and therefore two 'kinds' of plasma guns you can have. However, both guns work on similar principles.

The first kind of P-gun creates a burst of plasma using some method, then contains this plasma within a powerful electro-magnetic field, then accelerates it towards the target, and extends the field all the way to the target to keep the plasma confined and prevent blooming.

The second kind of P-gun creates a burst of plasma, confines it, then slams it with an extremely powerful pulse of electro-magnetic energy, accelerating it to a very apreciable fraction of the speed of light, so that the projectile will reach the target before the onset of blooming.

The first kind of gun would probably be relatively short-range without an immense energy source, such as that from a dedicated mini-fusion plant or a feed from an anti-mattet matter reactor. It's also more akin to a laser due to the EM field being projected all the way to the target. Almost certainly the projectile has a low velocity, probably between 500 or so to 5000 meters a second.

The second kind would be more akin to a particle beam weapon and distance would vary with the speed of the projectile, because more damage would come from the kinetic energy rather than thermal.

My idea for the basic part of the P-gun would be to slice off a small shaving of metal, run a massive electric current through it vaporizing it and turning it into a plasma, then accelerating this plasma to the target with either of the stated techniques.

4) Particle Weapons

These use ultra high energy beam of atoms [neutral] or electrons to damage a target by hitting it, thus disrupting it's atomic and molecular structure.

I prefer Particle Weapons that use atoms, since these cannot be deflected by an EM field, however, they are more complex than simply accelerating electrons. These accelerate a hydrogen ion to near the velocity of light, so each individual atom has an energy level between 100MeV and 1000MeV, father along they capture electrons from electron emitter electrodes, thusly being electrically neutralized. This creates an electrically neutral beam of high energy hydrogen atoms proceeding in a straight line at near the velocity of light.

This beam would be undeflectable by an EM field, or pulse, thus being more usefull in a theoretically high technology setting.

5) Lasers

Just a note. A laser will almost NEVER be visible in an atmosphere, and is completely invisible outside of the central axis in a vacuum. It can be visible if blooming occurs. [for a laser, it's because the energy densities of around a megajoule per square centimetter cause plasma breakdown in the air, defocusing the laser and causing it to lose energy to the atmosphere]

Most existing weaponized lasers are gas dynamic lasers, but their are other methods of creating them. They usually generate brief high energy pulses.

A million joules delivered as a laser pulse is roughly the same energy as 200g of high explosive, and has the same basic effect on a target. The primary damage mechanism is mechanical shear, caused by reaction [like a rocket] when the surface of the target is explosively evaporated.

Lasers have the advantages of travelling at the speed of light, so their is no need to adjust for target movement in terrestrial aplications. Some types can run on electricity so they need no finite source of ammo, but portable sources of electricty with sufficient capacity could be a problem. There is no recoil from a laser.

Some believe that mirrors or other countermeasures can reduce the effectiveness of high energy lasers, but this has not been demonstrated. Small defects in mirrors absorb the energy, and the defects rapidly expand across the surface. Protective mirroring on the surface of an object would be made less effective by incidental damage and dust and dirt on it's surface transferring energy to the mirror, creating defects, magnifying the energy absorbed, leading to the destruction of the mirror in an instant.

5) Power sources for most of these weapons could come from high-energy rapid discharge capacitors acting as the 'ammo' for the weapon.

If there are any questions, or more explanation is wanted, or another type of weapon needs explaning, please respond.

wouldnt a simple gas grenade or fog make the plasma, laser and particle weapon useless

lol explain Gauss weaponry lol

I'll leave the Gauss weaponry to someone else... but pay attention on the first stuff.... the plasma would simply consume the fog or gas, the laser would burn through it without being appreciably dispersed, and the particle beam wouldn't be hindered, either.

But... gas and fog would have no effect on the plasma, since it's basically a very hot, very fast moving bullet, particle weapons would drill straight through it, those few atoms that actually hit the intervening gas, [there's really almost no change in density, and that's the real thing that would stop these weapons... or not.] and again, a laser pulse would drill straight through, but it would lose energy in both cases. In all cases except for the plasma, which is either protected by the EM sheath as was earlier stated, or is moving way too damn fast for that intervening atmosphere to have any effect.

So basically search the world for the answers. Gee, I haven't thought of that!

So a soldier has more protection against these weaponry? I don't think it matters. If it's just the US invading a small developing country, then these weapons and a few thousand soldier will reduce it to dust. Against a world power, it's an arm for an arm.